SRV, which is an abbreviation for Service, is a DNS record, which permits you to use a domain for a particular service different from a website. By setting up a few SRV records, you are able to use the domain name with different providers and direct it to several servers at the same time, every single server managing a different service. You'll be able to specify the port number for the connection to each machine, so there will never be any interference. You can even set individual priorities and weight for 2 records which are employed for the same service, but forward to different servers for redundancy or load balancing. By having an SRV record you can use your domain name or a subdomain under it for a Voice-Over-IP server, for example, and have the specific software running on various machines with different providers. Which one a customer of yours will use is determined by the priority and weight values that you have set.